MAGNETIC POWDER LIQUID FOR MAGNETIC POWDER FLAW DETECTION AND METHOD OF MAGNETIC POWDER FLAW DETECTION

摘要

PURPOSE:To enable simultaneous flaw detection of defective parts in one direction and the direction perpendicular to the direction of an object to be inspected by using a magnetic powder liquid made by adding a synthetic resin emulsion having a function to form water-insoluble coating as a coating forming agent. CONSTITUTION:1-30pts.wt. synthetic resin emulsion having a function to form water- insoluble coating is used for 100pts.wt. liquid as a coating forming agent of magnetic powder liquid for magnetic powder flaw detection. Colored magnetic powder of the magnetic powder liquid is made by mixing a dyestuff such as oil red, a pigment such as permanent red GG to pure iron powder, iron oxide powder etc. using a synthetic resin as a binder. The synthetic resin emulsion added to the magnetic powder liquid is made by emulsifying a monomer selected from ethylene, acrylic acid, etc. in water using a surface-active agent, adding a polymerization initiator which is soluble in the monomer and insoluble in water and polymerizing by heating. By using this magnetic powder liquid and magnetic powder liquid in which a coating forming agent is not added, defect in one direction of the object to be inspected and in the direction perpendicular to the said direction can be examined simultaneously.